Audio media comprise an essentially ubiquitous feature of modern activity. Multimedia content, such as most modern movies, includes more than one kind of medium, such as both its video content and an audio soundtrack. Modern enterprises of virtually every kind and individuals from many walks of life use audio media content in a wide variety of both unique and related ways. Entertainment, commerce and advertising, education, instruction and training, computing and networking, broadcast, enterprise and telecommunications, are but a small sample of modern endeavors in which audio media content find common use.
Audio media include music, speech and sounds recorded on individual compact disks (CD) or other storage formats, streamed as digital files between server and client computers over networks, or transmitted with analog and digital electromagnetic signals. It has become about as familiar to find users listening to music from iPods™, MP3 players and CDs while mobile, commuting, etc. as at home on entertainment systems or other more or less stationary audio reproduction devices. Concerts from popular bands are streamed over the internet and enjoyed by users as audio and/or viewed as well in webcasts of the performance. Extremely portable lightweight, small form factor, low cost players of digital audio files have gained widespread popularity. Cellular phones, now essentially ubiquitous, and personal digital assistants (PDA) and handheld computers all have versatile functionality. Not just telecommunication devices, modern cell phones access the Internet and stream audio content therefrom.
As a result of its widespread and growing use, vast quantities of audio media content exist. Given the sheer quantity and variety of audio media content that exists, and the expanding growth of that content over time, an ability to identify content is of value. Media fingerprints comprise a technique for identifying media content. Media fingerprints are unique identifiers of media content from which they are extracted or generated. The term “fingerprint” is aptly used to refer to the uniqueness of these media content identifiers, in the sense that human beings are uniquely identifiable, e.g., forensically, by their fingerprints. While similar to a signature, media fingerprints perhaps even more intimately and identifiably correspond to the content. Audio and video media may both be identified using media fingerprints that correspond to each medium.
Audio media are identifiable with audio fingerprints, which are also referred to herein, e.g., interchangeably, as acoustic fingerprints. An audio fingerprint is generated from a particular audio waveform as code that uniquely corresponds thereto. Essentially, the audio fingerprint is derived from the audio or acoustic waveform. For instance, an audio fingerprint may comprise sampled components of an audio signal. As used herein, an audio fingerprint may thus refer to a relatively low bit rate representation of an original audio content file. Storing and accessing the audio fingerprints however may thus be efficient or economical, relative to the cost of storing an entire audio file, or portion thereof, from which it is derived.
Upon generating and storing an audio fingerprint, the corresponding waveform from which the fingerprint was generated may thereafter be identified by reference to its fingerprint. Audio fingerprints may be stored, e.g., in a database. Stored audio fingerprints may be accessed, e.g., with a query to the database in which they are stored, to identify, categorize or otherwise classify an audio sample to which it is compared. Acoustic fingerprints are thus useful in identifying music or other recorded, streamed or otherwise transmitted audio media being played by a user, managing sound libraries, monitoring broadcasts, network activities and advertising, and identifying video content (such as a movie) from audio content (such as a soundtrack) associated therewith.
The reliability of an acoustic fingerprint may relate to the specificity with which it identifiably, e.g., uniquely, corresponds with a particular audio waveform. Some audio fingerprints provide identification so accurately that they may be relied upon to identify separate performances of the same music. Moreover, some acoustic fingerprints are based on audio content as it is perceived by the human psychoacoustic system. Such robust audio fingerprints thus allow audio content to be identified after compression, decompression, transcoding and other changes to the content made with perceptually based audio codecs; even codecs that involve lossy compression (and which may thus tend to degrade audio content quality).
Audio fingerprints may be derived from an audio clip, sequence, segment, portion or the like, which is perceptually encoded. Thus the audio sequence may be accurately identified by comparison to its fingerprint, even after compression, decompression, transcoding and other changes to the content made with perceptually based audio codecs; even codecs that involve lossy compression, which may thus tend to degrade audio content quality (which may be practically imperceptible to detection). Moreover, audio fingerprints may function robustly over degraded signal quality of its corresponding content and a variety of attacks or situations such as off-speed playback.
Audio media content may be conceptually, commercially or otherwise related in some way to separate and distinct instances of content. The content that is related to the audio content which may include, but is not limited to other audio, video or multimedia content. For instance, a certain song may relate to a particular movie in some conceptual way. Other example may be text files or a computer graphics that relate to a given speech, lecture or musical piece in some commercial context.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section. Similarly, issues identified with respect to one or more approaches should not assume to have been recognized in any prior art on the basis of this section, unless otherwise indicated.